N.sup.6 -endo-bicyclo[2.2.1]heptyl adenosine as a diastereomeric mixture, i.e., is disclosed in US Application Ser. No. 772,983, now U.S. Pat. No. 4,714,697, as having a favorable ratio of affinities at A.sub.1 and A.sub.2 receptors and highly desirable analgesic and antiinflammatory properties.
It is now found that eachof the 1R- and 1S-diastereomers of N.sup.6 -endo-bicyclo[2.2.1]heptyl adenosine has particularly unexpected A.sub.1 and A.sub.2 receptor binding ratios.